Subdomain Lookup | Web-based subdomain scanner | WhoisXML API

Subdomain Lookup identifies the subdomains for a domain in web-based and shareable reports

2.3+ billionSubdomains
1 M+Subdomains discovered daily
2,864+TLDs tracking
10+ yearsof data crawling

What is Subdomain Lookup?

Subdomain Lookup allows you to identify all subdomains associated with any given domain name. With the aid of a database that’s updated daily, increasing by more than 1 million subdomains daily, we provide the most comprehensive and up-to-date information on all subdomains related to a given domain name in a convenient and unified format.

Subdomains Lookup


  • Based on up-to-date data

    All the subdomains that appear as search results come from a massive Subdomain Lookup database compiled through more than 10 years of data crawling and gets refreshed daily.

  • Readily available results

    Each lookup reveals a list of subdomains related to a domain of interest.

  • Subdomain checker with shareable findings

    Subdomains Lookup reports can be shared with colleagues instantly using custom URLs.

Our subdomain scanner tool lets you:

Enrich cybersecurity research

Enrich cybersecurity research

Attackers are known for using tons of subdomains to evade detection. Identify all the components of their infrastructure for more in-depth investigation results.

Identify dangling records

Subdomains left unused or forgotten are all too often left insufficiently protected. Make sure these haven’t been illegitimately modified for use in attacks.

Identify dangling records
Catch all possible attack culprits

Catch all possible attack culprits

Not all lists of indicators of compromise (IoCs) are exhaustive. Attackers may be using more subdomains than those identified as IoCs. Find all possible attack entry points to cover all your bases.

Gain much-needed competitive advantages

One way to get ahead of the competition is by staying toe-to-toe with business rivals. Their recently added subdomains can clue you into their up and coming product and service launches, as well as the business partners they might be working with.

Gain much-needed competitive advantages
Boost penetration testing efforts

Boost penetration testing efforts

Identify all your network’s weakest links by going deeper than the domain level. Consider your entire infrastructure so none of your systems are left exposed to threats or risks.

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